[The serotonin-dependent suppression of the immune response by kappa-opiate receptors].

The modulating effect of the kappa-opiate agonist, rimorphin, on the immune response was studied. This opioid in all the doses tested (1, 10 and 100 mkg/kg) was found to cause inhibition of the immune reaction as compared to the control CBA mice which received saline only. The dissection of the pituitary stalk prevented the inhibitory effect of rimorphin on the immunity. The opioid-induced immunosuppression was shown to be due to interaction with the serotoninergic system since it had no effect after preliminary blockade of S-2 serotonin postsynaptic receptors with cyproheptadine.